Red Macroalgae as Sources of Antioxidant and Multifunctional Ingredients for Functional Foods: A Biorefinery Approach

Area of Science:

• Marine biotechnology
• Food science
• Nutraceuticals

Background:

• Cognitive decline is linked to oxidative stress, cholinergic dysfunction, and metabolic imbalance.
• Marine algae are sustainable sources of bioactive compounds for functional foods.
• Red macroalgae from Madeira Archipelago were selected for investigation.

Purpose of the Study:

• To explore the multifunctional potential of three red macroalgae species: *Asparagopsis taxiformis*, *Grateloupia lanceola*, and *Nemalion elminthoides*.
• To evaluate extracts obtained through a sequential biorefinery approach for antioxidant and health-relevant bioactivities.
• To support the use of these algae as functional food ingredients.

Main Methods:

• A sequential biorefinery approach was used to obtain protein, ethanolic (phenolic-rich), and polysaccharide fractions.
• Antioxidant activity was assessed using ORAC, DPPH, FRAP, and FIC assays.
• Enzyme inhibition relevant to cognitive function (acetylcholinesterase, butyrylcholinesterase) and metabolic health (α-glucosidase) was evaluated.

Main Results:

• Protein extracts, especially from *N. elminthoides*, showed significant antioxidant capacity via hydrogen atom transfer.
• Ethanolic extracts exhibited multifunctional properties, including radical scavenging, metal chelation, and enzyme inhibition.
• Polysaccharide fractions contributed to iron chelation and reducing capacity, complementing other activities.

Conclusions:

• Madeira red macroalgae possess significant antioxidant and bioactivities relevant to neuroprotection and glycemic regulation.
• Biorefinery processing is crucial for maximizing the nutritional and health benefits of these marine resources.
• These algae show promise as functional food ingredients for improving health outcomes.